| Message ID | 1433170082-117462-4-git-send-email-andriy.shevchenko@linux.intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Monday, June 01, 2015 05:47:57 PM Andy Shevchenko wrote: > From: Heikki Krogerus <heikki.krogerus@linux.intel.com> > > If the parent is still suspended when driver probe is > attempted, the result may be failure. > > For example, if the parent is a PCI MFD device that has been > suspended when we try to probe our device, any register > reads will return 0xffffffff. > > To fix the problem, making sure the parent is always awake > before attempting driver probe. > > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > --- > drivers/base/dd.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > index e843fdb..cfbeff3 100644 > --- a/drivers/base/dd.c > +++ b/drivers/base/dd.c > @@ -399,6 +399,8 @@ EXPORT_SYMBOL_GPL(wait_for_device_probe); > * > * This function must be called with @dev lock held. When called for a > * USB interface, @dev->parent lock must be held as well. > + * > + * If device has a parent it will be powered on during device's probe(). > */ > int driver_probe_device(struct device_driver *drv, struct device *dev) > { > @@ -410,10 +412,16 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) > pr_debug("bus: '%s': %s: matched device %s with driver %s\n", > drv->bus->name, __func__, dev_name(dev), drv->name); > > + if (dev->parent) > + pm_runtime_get_sync(dev->parent); > + For some bus types that will resume and suspend the parent for many times in a row in device_attach() until an appropriate driver is found. Would it be more efficient to call it once before the bus_for_each_drv() loop in there? > pm_runtime_barrier(dev); > ret = really_probe(dev, drv); > pm_request_idle(dev); > > + if (dev->parent) > + pm_runtime_put_sync(dev->parent); Is there anything particularly wrong with calling pm_runtime_put() here instead? > + > return ret; > } > >
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index e843fdb..cfbeff3 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -399,6 +399,8 @@ EXPORT_SYMBOL_GPL(wait_for_device_probe); * * This function must be called with @dev lock held. When called for a * USB interface, @dev->parent lock must be held as well. + * + * If device has a parent it will be powered on during device's probe(). */ int driver_probe_device(struct device_driver *drv, struct device *dev) { @@ -410,10 +412,16 @@ int driver_probe_device(struct device_driver *drv, struct device *dev) pr_debug("bus: '%s': %s: matched device %s with driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); + if (dev->parent) + pm_runtime_get_sync(dev->parent); + pm_runtime_barrier(dev); ret = really_probe(dev, drv); pm_request_idle(dev); + if (dev->parent) + pm_runtime_put_sync(dev->parent); + return ret; }